PARIS (Agence France-Presse)--Farmers who grow genetically engineered crops may need to carry out additional pesticide sprayings in order to maximize yields, in what could be a new blow to the marketing hopes of biotechnology companies, the British weekly New Scientist reports.
Agricultural biotechnology firms have pitched so-called transgenic crops to farmers, in part, by saying that these plants can offer big savings on costly herbicides and pesticides.
This is because the plants are resistant to certain herbicides, such as the powerful Roundup variety, which means that a field can be given an easy one-off spraying to kill weeds
without damaging the crop, or because they have been engineered to be poisonous to certain bugs.
But, New Scientist says, the Swiss giant Novartis has just filed patent applications that imply farmers may need to carry out more sprayings if they want to get the best out of their crops.
The applications were filed after Novartis realized its flagship transgenic product, Bt corn, which successfully repels a pest called corn borer, turned out to be vulnerable to sap-sucking insects, such as flea beetles.
"To find a way round the problem, Novartis scientists tried applying different combinations of the company's pesticides to the Bt maize. Their patents identify combinations of pesticides that could raise yields of the corn by 20%," said the report, carried in Saturday's issue.
The patents cover a long list of transgenic products, including corn, cereals, soybeans, potatoes, rice, cotton and mustard, it said.
Novartis, in its response, said the pesticides mentioned in the patents only attacked targeted pests and not other bugs.